I don't have any idea on magnetic belt but to reduce belly fat do pranks for 10 mins every day and drink cinnamon water every morning after wake up.
preparation of cinnamon water:
mix cinnamon powder, lemon and honey in warm water . have it every morning daily.

Do Yoga ( surya namska) start doing daily by 5 surya namskar and drink cinnamon powder honey and water one cup. Put one tp of powder in one cup water and boil it for 15 minutes and in half up of it add one tp honey. Take it morning half and before sleeping half cup